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1. #XZ COMPRESSION 7Z ARCHIVE#
2. #XZ COMPRESSION 7Z RAR#
3. #XZ COMPRESSION 7Z CODE#
4. #XZ COMPRESSION 7Z LICENSE#

The key is generated from a user-supplied passphrase using an algorithm based on the SHA-256 hash function. The 7z format supports encryption with the AES algorithm with a 256-bit key.

#XZ COMPRESSION 7Z RAR#

Similar executable pre-processing technology is included in other software the RAR compressor features displacement compression for 32-bit x86 executables and IA-64 executables, and the UPX runtime executable file compressor includes support for working with 16-bit values within DOS binary files. Delta encoding – delta filter, basic preprocessor for multimedia data.Near jump, near call, conditional near jump targets are split out and compressed separately in another stream. BCJ2 is an improvement on BCJ, adding additional x86 jump/call instruction processing. BCJ2– Pre-processor for 32-bit x86 executables.Normalise target addresses of near jumps and calls from relative distances to absolute destinations. BCJ – Converter for 32-bit x86 executables.For x86, this means that near jumps, calls and conditional jumps (but not short jumps and conditional jumps) are converted from the machine language "jump 1655 bytes backwards" style notation to normalized "jump to address 5554" style notation all jumps to 5554, perhaps a common subroutine, are thus encoded identically, making them more compressible. The LZMA SDK comes with the BCJ and BCJ2 preprocessors included, so that later stages are able to achieve greater compression: For x86, ARM, PowerPC (PPC), IA-64 Itanium, and ARM Thumb processors, jump targets are 'normalized' before compression by changing relative position into absolute values. 7-Zip contains a from-scratch DEFLATE encoder that frequently beats the de facto standard zlib version in compression size, but at the expense of CPU usage.Ī suite of recompression tools called AdvanceCOMP contains a copy of the DEFLATE encoder from the 7-Zip implementation these utilities can often be used to further compress the size of existing gzip, ZIP, PNG, or MNG files. Deflate is found in several file formats including ZIP, gzip, PNG and PDF.

DEFLATE – Standard algorithm based on 32 kB LZ77 and Huffman coding.PPMd – Dmitry Shkarin's 2002 PPMdH (PPMII (Prediction by Partial matching with Information Inheritance) and cPPMII (complicated PPMII)) with small changes: PPMII is an improved version of the 1984 PPM compression algorithm (prediction by partial matching).Bzip2 uses two reversible transformations BWT, then Move to front with Huffman coding for symbol reduction (the actual compression element). Bzip2 – The standard Burrows–Wheeler transform algorithm.LZMA2 – modified version of LZMA providing better multithreading support and less expansion of incompressible data.

The LZ stage is followed by entropy coding using a Markov chain-based range coder and binary trees.

#XZ COMPRESSION 7Z ARCHIVE#

to re-assemble an archive from a set of multi-part component files). Support for multi-part archives : e.g.Compression and encryption of archive headers.Support for solid compression, where multiple files of like type are compressed within a single stream, in order to exploit the combined redundancy inherent in similar files.Large file support (up to approximately 16 exbibytes, or 2 64 bytes).High compression ratios (depending on the compression method used).Open, modular architecture that allows any compression, conversion, or encryption method to be stacked.The 7z format provides the following main features: There have been additional third-party attempts at writing more concrete documentation based on the released code.

#XZ COMPRESSION 7Z CODE#

The specification can be found in plain text format in the 'doc' sub-directory of the source code distribution. The official, informal 7z file format specification is distributed with 7-Zip's source code since 2015. The latest stable version of 7-Zip and LZMA SDK is version 22.01. The LZMA SDK 4.62 was placed in the public domain in December 2008. The 7-Zip program is publicly available under the terms of the GNU Lesser General Public License. The 7z format initially appeared as implemented by the 7-Zip archiver.

#XZ COMPRESSION 7Z LICENSE#

Yes: GNU Lesser General Public License / Public domainħz is a compressed archive file format that supports several different data compression, encryption and pre-processing algorithms.